How do you integrate \[\int {{x^2}{e^{{x^2}}}} dx\] using integration by parts?
Answer
624.3k+ views
Hint: Here, we will use ILATE and choose our first and second term. Then we will use the integration by parts formula and substitute the value in it. Finally, we will solve the equation by integrating and differentiating terms in it to get the required answer.
Complete step-by-step answer:
We have to integrate\[\int {{x^2}{e^{{x^2}}}} dx\]
So by ILATE method
First Term \[ = u\left( x \right) = {x^2}\]
Second Term \[ = v\left( x \right) = {e^{{x^2}}}\]
But to integrate \[{e^{{x^2}}}\]we need a \[x\]so that we can use substitution.
\[u\left( x \right) = x\]
\[v\left( x \right) = x \times {e^{{x^2}}}\]
Now as we know formula of by parts integration is:
\[\int {\left( {u\left( x \right)v\left( x \right)} \right)dx = u\left( x \right)\int {v\left( x \right)dx - \int {\left( {\dfrac{{d\left( {u\left( x \right)} \right)}}{{dx}}\int {v\left( x \right)dx} } \right)dx} } } \]
Substituting the value in the above equation, we get,
\[\int {{x^2}{e^{{x^2}}}} dx = x\int {x \times {e^{{x^2}}}dx - \int {\left( {\dfrac{{d\left( x \right)}}{{dx}}\int {x \times {e^{{x^2}}}} dx} \right)dx} } \]….\[\left( 2 \right)\]
To integrate the term inside the integration sign we will let
\[{x^2} = t\]
Now, differentiating with respect to\[x\]we get,
\[\begin{array}{l}2x = \dfrac{{dt}}{{dx}}\\x \times dx = \dfrac{{dt}}{2}\end{array}\]
Substituting above value in equation (2) we get,
\[\int {{x^2}{e^{{x^2}}}} dx = x\int {\dfrac{{{e^t}}}{2}dt - \int {\left( {\dfrac{{d\left( x \right)}}{{dx}}\int {\dfrac{{{e^t}}}{2}} dt} \right)dt} } \]
Now integrating \[{e^t}\]and differentiating\[x\] we get,
\[\int {{x^2}{e^{{x^2}}}} dx = x \times \dfrac{{{e^t}}}{2} - \int {1 \times \dfrac{{{e^t}}}{2}dx} \]
Replacing back the value of \[t = {x^2}\]we get,
\[\begin{array}{l}\int {{x^2}{e^{{x^2}}}} dx = \dfrac{{x{e^{{x^2}}}}}{2} - \int {\dfrac{{{e^{{x^2}}}}}{2}dx} \\\int {{x^2}{e^{{x^2}}}} dx = \dfrac{{x{e^{{x^2}}}}}{2} - \dfrac{1}{2}\int {{e^{{x^2}}}dx} \end{array}\]
Now we can’t further solve this equation because \[\int {{e^{{x^2}}}dx} \] has no closed form solution.
Note:
Integration is used to calculate areas, volume, and displacement. Integration is an inverse process of differentiation. The two types of integral are definite and Indefinite integral. Definite integral has both upper and lower limits on a real line. Indefinite integral on the other side is without defined upper and lower limits. Production rule is used when we have to find the integration of two values inside the integration side; this method is also known as Integration by parts. By using integration by parts we reduce the integrals in their standard form.
Complete step-by-step answer:
We have to integrate\[\int {{x^2}{e^{{x^2}}}} dx\]
So by ILATE method
First Term \[ = u\left( x \right) = {x^2}\]
Second Term \[ = v\left( x \right) = {e^{{x^2}}}\]
But to integrate \[{e^{{x^2}}}\]we need a \[x\]so that we can use substitution.
\[u\left( x \right) = x\]
\[v\left( x \right) = x \times {e^{{x^2}}}\]
Now as we know formula of by parts integration is:
\[\int {\left( {u\left( x \right)v\left( x \right)} \right)dx = u\left( x \right)\int {v\left( x \right)dx - \int {\left( {\dfrac{{d\left( {u\left( x \right)} \right)}}{{dx}}\int {v\left( x \right)dx} } \right)dx} } } \]
Substituting the value in the above equation, we get,
\[\int {{x^2}{e^{{x^2}}}} dx = x\int {x \times {e^{{x^2}}}dx - \int {\left( {\dfrac{{d\left( x \right)}}{{dx}}\int {x \times {e^{{x^2}}}} dx} \right)dx} } \]….\[\left( 2 \right)\]
To integrate the term inside the integration sign we will let
\[{x^2} = t\]
Now, differentiating with respect to\[x\]we get,
\[\begin{array}{l}2x = \dfrac{{dt}}{{dx}}\\x \times dx = \dfrac{{dt}}{2}\end{array}\]
Substituting above value in equation (2) we get,
\[\int {{x^2}{e^{{x^2}}}} dx = x\int {\dfrac{{{e^t}}}{2}dt - \int {\left( {\dfrac{{d\left( x \right)}}{{dx}}\int {\dfrac{{{e^t}}}{2}} dt} \right)dt} } \]
Now integrating \[{e^t}\]and differentiating\[x\] we get,
\[\int {{x^2}{e^{{x^2}}}} dx = x \times \dfrac{{{e^t}}}{2} - \int {1 \times \dfrac{{{e^t}}}{2}dx} \]
Replacing back the value of \[t = {x^2}\]we get,
\[\begin{array}{l}\int {{x^2}{e^{{x^2}}}} dx = \dfrac{{x{e^{{x^2}}}}}{2} - \int {\dfrac{{{e^{{x^2}}}}}{2}dx} \\\int {{x^2}{e^{{x^2}}}} dx = \dfrac{{x{e^{{x^2}}}}}{2} - \dfrac{1}{2}\int {{e^{{x^2}}}dx} \end{array}\]
Now we can’t further solve this equation because \[\int {{e^{{x^2}}}dx} \] has no closed form solution.
Note:
Integration is used to calculate areas, volume, and displacement. Integration is an inverse process of differentiation. The two types of integral are definite and Indefinite integral. Definite integral has both upper and lower limits on a real line. Indefinite integral on the other side is without defined upper and lower limits. Production rule is used when we have to find the integration of two values inside the integration side; this method is also known as Integration by parts. By using integration by parts we reduce the integrals in their standard form.
Recently Updated Pages
What is BLO What is the full form of BLO class 8 social science CBSE

Explain the Treaty of Vienna of 1815 class 10 social science CBSE

10 examples of friction in our daily life

Draw a diagram of nephron and explain its structur class 11 biology CBSE

Write structures of the following compounds i 2 Chloro3methylpentane class 11 chemistry CBSE

A Paragraph on Pollution in about 100-150 Words

Trending doubts
Draw a labelled sketch of the human eye class 12 physics CBSE

Which are the Top 10 Largest Countries of the World?

Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE

Draw ray diagrams each showing i myopic eye and ii class 12 physics CBSE

Which is the correct genotypic ratio of mendel dihybrid class 12 biology CBSE

What is the Full Form of PVC, PET, HDPE, LDPE, PP and PS ?

